Restrictor/protector of passenger in vehicle

ABSTRACT

A main controlling section of a controlling unit ( 13 ), when judging a collision risk, drives a motor ( 12 ) in a direction of retracting a seat belt ( 3 ) and raises tension of the seat belt ( 3 ). The main controlling section, when tension of the seat belt ( 3 ) reaches a predetermined value, judges that a locking signal is input and has the motor ( 12 ) continue retracting driving of the seat belt ( 3 ) for a predetermined time and, when a locking signal is not input, decreases a driving power of the motor ( 12 ) and lowers tension of the seat belt ( 3 ). Even when a collision risk signal is erroneously output from a collision risk judging section ( 11 ) and, so long as a locking signal is not output from the locking signal producing section ( 18 ), since control is immediately exerted so that tension of the seat belt ( 3 ) is lowered, it is possible to avoid an unpleasant feeling to a vehicle occupant (A) caused by comparative long-duration and useless restraining using the seat belt ( 3 ).

TECHNICAL FIELD

The present invention relates to a vehicle occupant restraining andprotecting apparatus to restrain an occupant of a vehicle on a seat attime of occurrence of a collision of a vehicle.

BACKGROUND ART

As a belt retracting device (belt retractor) to retract a seat belt usedto safely keep a vehicle occupant or a like on a seat, conventionally,an emergency locking-type retractor equipped with an emergencylocking-mechanism to automatically lock the retractor by using aninertia detecting means that acts to rapid acceleration, collision orrapid deceleration is used (For example, Japanese Patent ApplicationLaid-open No. Sho 50-79024, Japanese Patent Publication No. Sho59-21624, and Japanese Utility Model Publication No. Hei 02-45088).

The conventional belt retractor is controlled in a manner in which, forexample, when collision is judged as unavoidable, a seat belt (webbing)is reeled by using a motor to raise tension of the seat belt and, afterthe tension reaches a predetermined level, the tension of the seat beltis lowered.

By controlling as above, for example, even when the judgement that thecollision would be unavoidable was not correct and the collision did notoccur actually, needless restraining can be avoided and no unpleasantfeeling is given to a vehicle occupant.

However, if the belt retractor is so controlled that the tension of theseat belt is lowered immediately after the tension has reached apredetermined level following the rise of the tension of the seat belt,the seat belt is locked for drawing before the tension is restored toits original level reached before the rise in the tension. This isbecause, when the seat belt is drawn out, the locking mechanism is stillkept in a lockable state in which the drawing of a seat-belt isinhibited (for example, in a state in which a condition is being metunder which the drawing of seat-belt to be performed when a speed of avehicle is decelerated at a level exceeding a predetermined one; forexample, due to a driver's rapid operation of a brake is locked). Here,there is a problem in that, in such a case as above, it is necessarythat the seat belt is reeled again to release the locking of drawing,thus causing a vehicle occupant to be further restrained which gives anunpleasant feeling to a vehicle occupant.

To solve this problem, technology is disclosed in, for example, JapanesePatent Application Laid-open No. Hei 11-198760) in which a beltretractor is controlled in a manner in which, when the collision isjudged as unavoidable, a seat belt is reeled to raise a tension of theseat belt and, after the tension of the seat belt reaches apredetermined level, the reeling operations are continued for apredetermined reeling-continuing time (for example, 5 seconds) and, atthe best time when the condition for locking the drawing is judged to benot met, the tension of the seat belt is lowered.

However, according to the above conventional technology, in the abovereeling-continued time is included time during which the condition forlocking of drawing is being met (that is, time during which the lockingmechanism is in a lockable state) and, therefore, it is necessary thatthe reeling continuing time is set to be longer than the time duringwhich the above condition is met.

Additionally, since the time during which the condition for locking ofdrawing varies depending upon a way of pressing a brake pedal, a speedof a vehicle reached before an operator's rapid operation of a brake,and a way of action of an inertial force to be exerted on a vehicle whencollision is avoided by the rapid operation of the brake, in order toavoid an unpleasant feeling that may be given to a vehicle occupant dueto a repeated rise in the tension of the seat belt required forreleasing the locking described above, it is necessary that the abovereeling-continuing time is set to be as long as possible.

As a result, the conventional belt retractor has a problem in that, evenwhen a judgement that collision is unavoidable was not correct and thecollision did not occur, a vehicle occupant must endure a pain withbeing restrained on a seat during a period of the fixed andcomparatively long time.

In view of the above, it is an object of the present invention toprovide a restraining and protecting apparatus for a vehicle occupantwhich is capable of avoiding needless and long-time restraining of thevehicle occupant by a seat belt and of not giving an unpleasant feelingto the vehicle occupant.

DISCLOSURE OF THE INVENTION

To solve the above problem, the present invention as set forth in Claim1 is characterized in that a restraining and protecting apparatus for avehicle occupant on a seat including a belt adjusting unit to adjust astate in which the vehicle occupant is restrained using a seat belt byincreasing or decreasing the seat belt to be drawn out in length, a beltlocking mechanism to prevent the seat belt from being drawn out bylocking the seat belt, an “immediately before collision” signalproducing section to produce and output the “immediately beforecollision” signal immediately before occurrence of a collision of thevehicle, a locking signal producing section to produce and output alocking signal when it is predicted at least that the belt lockingmechanism is in a lockable state where inhibition of drawing out is madepossible when the seat belt is going to be drawn out, a controllingsection to control the belt adjusting unit based on the “immediatelybefore collision” signal to be input and the locking signal to be input,and wherein the controlling section exerts control in a manner in which,when the “immediately before collision” signal is input, the beltadjusting unit increases the state in which the vehicle occupant isrestrained using the seat belt and in which, when the locking signal isnot input, the belt adjusting unit weakens the state in which thevehicle occupant is restrained using the seat belt.

Also, the present invention as set forth in Claim 2 is related to therestraining and protecting apparatus for the vehicle occupant as definedin Claim 1 and is characterized in that the belt locking mechanism inthe lockable state, when the belt adjusting unit is controlled by thecontrolling section so as to increase the state in which the vehicle thevehicle occupant is restrained using the seat belt, is put into a stateof releasing the locking in which the seat belt is able to be drawn out.

Also, the present invention as set forth in Claim 3 is related to therestraining and protecting apparatus for the vehicle occupant as definedin Claim 1 or Claim 2 and is characterized in that the controllingsection exerts control so that, while the locking signal is input, thebelt adjusting unit increases and maintains the state in which thevehicle occupant is restrained using the seat belt.

Also, the present invention as set forth in Claim 4 is related to therestraining and protecting apparatus for the vehicle occupant as definedin Claim 3 and is characterized in that the controlling section exertscontrol so that the belt adjusting unit, when a predetermined timeelapses after the locking signal has been input, weakens the state inwhich the vehicle occupant is restrained using the seat belt.

Also, the present invention as set forth in Claim 5 is related to therestraining and protecting apparatus for the vehicle occupant as definedin any one of Claim 1 to Claim 4, wherein the controlling section exertscontrol when the “immediately before collision” signal is input so thatthe belt adjusting unit increases the state in which the vehicleoccupant is restrained using the seat belt and that the belt adjustingunit, the state in which the vehicle occupant is restrained to apredetermined extent and when the locking signal is not input, weakensthe state in which the vehicle occupant is restrained using the seatbelt.

Also, the present invention as set forth in Claim 6 is related to therestraining and protecting apparatus for the vehicle occupant as definedin any one of Claim 1 to Claim 5 and is characterized in that thelocking signal producing section outputs the locking signal when atleast part of conditions under which drawing of the seat belt isinhibited by the belt locking mechanism is met.

Also, the present invention as set forth in Claim 7 is related to therestraining and protecting apparatus for the vehicle occupant as definedin Claim 6 and is characterized in that the seat belt is locked undercondition that acceleration in a back-and-forth or lateral direction ofthe vehicle exceeds a predetermined value.

Also, the present invention as set forth in Claim 8 is related to therestraining and protecting apparatus for the vehicle occupant as definedin Claim 6 and is characterized in that the seat belt is locked undercondition that acceleration at which the seat belt is drawn out exceedsa predetermined value.

Also, the present invention as set forth in Claim 9 is related to therestraining and protecting apparatus for the vehicle occupant as definedin Claim 7 or Claim 8 and is characterized in that the accelerationincludes acceleration in a direction being reverse to a direction of avelocity of the vehicle.

Also, the present invention as set forth in Claim 10 is related to therestraining and protecting apparatus for the vehicle occupant as definedin any one of Claim 1 to Claim 5 and is characterized in that thelocking signal producing section, when a state in which the belt lockingmechanism is in a lockable state is detected, outputs the lockingsignal.

Also, the present invention as set forth in Claim 11 is related to therestraining and protecting apparatus for the vehicle occupant as definedin any one of Claim 1 to Claim 10 and is characterized in that the beltadjusting unit has a motor to retract the seat belt and that thecontrolling section, where the “immediately before collision” signal isinput, controls the motor to increase its driving power and to increasethe state in which the vehicle occupant is restrained using the seatbelt and exerts control so that, the belt adjusting unit, when thelocking signal is not input, weakens the state in which the vehicleoccupant is restrained using the seat belt.

Also, the present invention as set forth in Claim 12 is related to therestraining and protecting apparatus for the vehicle occupant as definedin Claim 11 and is characterized in that the controlling section, whilethe locking signal is input, controls the motor serving as the beltadjusting unit so as to have the seat belt retracted.

Also, the present invention as set forth in Claim 13 is related to therestraining and protecting apparatus for the vehicle occupant as definedin any one of Claim 1 to Claim 12 and is characterized in that the“immediately before collision” signal producing section, based on adetection signal obtained from a non-contact type distance sensor,calculates a speed of the vehicle relative to an obstruction existing infront of the vehicle and, based on a result from calculation, judges asto whether there is a possibility of occurrence of collision between thevehicle and the obstruction and also judges, when there is thepossibility of the collision, as to whether the avoidance of thecollision is possible or not

Also, the present invention as set forth in Claim 14 is related to therestraining and protecting apparatus for the vehicle occupant as definedin any one of Claim 1 to Claim 13 and is characterized in that the“immediately before collision” signal producing section, when adetection of an operation for collision avoidance is made, outputs the“immediately before collision” signal.

Furthermore, the present invention as set forth in Claim 15 is relatedto the restraining and protecting apparatus for the vehicle occupant asdefined in Claim 14 and is characterized in that the “immediately beforecollision” signal producing section outputs the “immediately beforecollision” signal when detection of a rapid brake operation or a rapidhandle operation for collision avoidance is made by being recognizedthat acceleration in a back-and-forth or lateral direction of thevehicle exceeds a predetermined value.

With the configurations of the present invention, even if the collisionrisk signal is output erroneously from the collision risk judgingsection, unless the locking signal is output from the locking signalproducing section, control is exerted so that the tension of the seatbelt is immediately lowered and, therefore, it is possible to avoidoccurrence of giving an unpleasant feeling to the vehicle occupantcaused by needless restraining for a comparatively long time.

Moreover, even if the locking signal is output from the locking signalproducing section, reeling of the seat belt is continued for apredetermined duration time for reeling by the motor even after thetension of the seat belt reaches a predetermined tension and, therefore,when the non-locking signal is output within the reeling continuationtime, even if the tension of the seat belt is lowered, drawing of theseat belt is not locked. As a result, it is possible to prevent theoccurrence of giving an unpleasant feeling to the vehicle occupantcaused by restraining of the vehicle occupant occurring when the seatbelt is again reeled to release the drawing locking.

Moreover, unlike in the case of the conventional technology in which thereeling continuation time is set at fixed time including the time atwhich a condition for locking of drawing is met and, during the fixedtime, the driving operation for reeling is continued, in thisembodiment, so long as the locking signal is being output from thelocking signal producing section, the driving operation for the reelingby the motor is continued and, therefore, a needless rise in the tensionof the seat belt can be prevented and wasteful restraining time can besaved.

Also, by stopping the driving operation for reeling to lower the tensionof the seat belt after the predetermined reeling continuation time haselapsed, for example, the lockable state occurs in a long steep slopingroad and, when the locking signal is output, a state in which thetension of the seat belt is high continues for comparatively long, thuspreventing occurrence of giving an unpleasant feeling to the vehicleoccupant. Also, it is possible to prevent breakage and/or degradation ofthe belt adjusting unit caused by long operation for the reeling and toachieve a long life of the belt adjusting unit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram schematically showing configurations of a seat beltdevice of a first embodiment of the present invention.

FIG. 2 is a diagram showing configurations of a belt retractor of theseat belt device.

FIG. 3 is a block diagram showing configurations of a controlling unitof the above belt retractor.

FIG. 4 is a block diagram showing configurations of a locking signalproducing section of the above belt retractor.

FIG. 5 is a circuit diagram showing configurations of a potentiometer ofthe above belt retractor.

FIG. 6 is a circuit diagram showing configurations of a motor drivingcircuit of the above belt retractor.

FIG. 7 is an expanded perspective view showing a part of theconfigurations of the above belt retractor.

FIG. 8 is an expanded perspective view showing another part of theconfigurations of the above belt retractor.

FIG. 9 is a cross-sectional view showing configurations of a beltlocking mechanism of the seat belt device.

FIG. 10 is a diagram explaining a ratchet wheel of the above beltlocking mechanism.

FIG. 11 is a diagram showing configurations of a locking arm of theabove belt locking mechanism.

FIG. 12 is a diagram showing configurations of an inertia plate of theabove belt locking mechanism.

FIGS. 13 to 15 are diagrams explaining operations of the belt lockingmechanism.

FIG. 16 is a flowchart explaining operations of the above seat beltdevice.

FIG. 17 is a flowchart explaining operations of the above locking signalproducing section.

FIG. 18 is a diagram showing configurations of a belt retractor of aseat belt device of a second embodiment of the present invention.

FIG. 19 is a diagram explaining configurations of a vehicle accelerationdetecting section and a locking signal producing section making up thebelt retractor and showing a state in which the belt retractor is notlocked.

FIG. 20 is a diagram explaining configurations of the vehicle bodyacceleration detecting section and the locking signal producing sectionmaking up the belt retractor and showing a state in which the beltretractor is locked.

FIG. 21 is a diagram explaining configurations of the locking signalproducing section.

FIG. 22 is a circuit diagram showing configurations of a locking signaloutputting section of the locking signal producing section.

FIG. 23 is a diagram explaining configurations of a seat belt device ofa third embodiment of the present invention.

FIG. 24 is a diagram explaining configurations of a seat belt device ofa fourth embodiment of the present invention.

FIG. 25 is a diagram explaining configurations of a modified example ofthe seat belt device of the third embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention are described byreferring to drawings. Concrete descriptions are made by using theembodiments.

First Embodiment

FIG. 1 is a diagram schematically showing configurations of a seat beltdevice 1 of the first embodiment of the present invention. FIG. 2 is adiagram showing configurations of a belt retractor 4 of the seat beltdevice 1. FIG. 3 is a block diagram showing configurations of acontrolling unit 13 of the belt retractor 4.

The seat belt device (restraining and protecting apparatus for vehicleoccupants) 1 of the first embodiment, as shown in FIG. 1 to FIG. 13,includes a seat belt (webbing) 3 to restrain a vehicle occupant A on aseat 2 of a vehicle, a belt retractor 4 to reel the seat belt 3, athrough anchor 5 to fold the seat belt 3 back in the vicinity of ashoulder of the vehicle occupant, a buckle 6 to be placed on a hipportion of the vehicle occupant A through which the seat belt 3 isfitted, a tongue plate 7 to be connected to the buckle 6 in anassociated manner, an anchor 8 to fix an end of the seat belt 3 to avehicle body, a seat belt wearing detecting section 9 embedded in thebuckle 6 to detect wearing of the seat belt 3, and a collision riskjudging section (“immediately before collision” signal producingsection) 11 to judge the risk of collision or a like of a vehicle.

The belt retractor 4, as shown in FIG. 2, has a controlling unit 13 tocontrol a motor (belt adjusting unit) 12 used to reel the seat belt 3, areel 15 to wind the seat belt 3 around a frame 14, a reel shaft 16 to beconnected to a leftmost end of the reel 15 on which the reel shaft 16serving as a central shaft for rotation of the reel 15 to be placed in amanner to rotate freely, and a belt locking mechanism (belt lockingmechanism) 17 to be placed on a rightmost end of the reel shaft 16 andto be used to lock drawing of the seat belt 3. Moreover, to thecontrolling unit 13 is electrically connected a locking signal producingsection (locking signal producing section) 18 to produce a lockingsignal and to feed the produced signal to the controlling unit 13 whenthe belt locking mechanism 17 is in a lockable state in which the seatbelt 3 is to be drawn.

The belt locking mechanism 17 has a function (VSI function) to lockdrawing of the seat belt 3 when the vehicle is decelerated to apredetermined level or a shock occurs and a function (WSI function) tolock drawing of the seat belt 3 when the seat belt 3 is rapidly drawn atthe acceleration exceeding a predetermined level.

Moreover, the belt locking mechanism 17 is so configured that, even in astate in which the drawing of the seat belt 3 is being locked, the seatbelt 3 can be reeled by the motor 12.

Also, the belt locking mechanism 17 is so configured that, even afterdrawing of the seat belt 3 is locked, the locking of drawing is releasedby operations of reel driving performed by the motor 12.

Also, the reel shaft 16 is a torsional shaft having a function ofabsorbing energy. That is, if the seat belt 3 is drawn by the beltlocking mechanism 17 by strong force with the reel shaft 16 being lockedat its right end, plastic deformations of the reel shaft 16 appear in amanner in which the reel shaft 16 itself is distorted around its axis.This allows the seat belt 3 to be drawn out and shock energy acting on abody of the vehicle occupant A to be absorbed by the seat belt 3.

A pulley 19 being fixed to the reel shaft 16 is connected to a pulley 22fixed to a shaft of the motor 12 via a power transfer belt (timing belt)21. In portions externally surrounding the pulleys 19 and 22 are formeda predetermined number of external teeth respectively and also at theinner radius of the power transfer belt 21 is formed a predeterminednumber of internal teeth.

Each of the teeth of the pulley 19 of the reel shaft 16, and the pulley22 of the motor 12 engage in the power transfer belt 21 in properquantities and the rotation of the motor 12 is transferred to the reelshaft 16.

The motor 12 is fixed to the frame 14 at, at least, in two points andoperates according to an instruction signal of the controlling unit 13.

FIG. 5 is a circuit diagram showing configurations of a potentiometer 23of the belt retractor 4. The potentiometer 23 placed at the leftmost endof the reel shaft 16, as shown in FIG. 5, includes a resistor 23 a, toboth ends of which a voltage is applied, and a slider 23 b that rotatesin synchronization with rotation of the reel shaft 16 and outputs avoltage corresponding to amounts of the rotation relative to a referenceposition of the reel shaft 16 to the controlling unit 13.

By configuring as above, for example, amounts of drawing of the seatbelt 3 can be estimated. It is possible to estimate an amount oflooseness of the seat belt 3 by comparing a voltage value in a state inwhich the seat belt 3 has no looseness with a voltage value in a statein which the seat belt 3 is drawn out.

The controlling unit 13, as shown in FIG. 3, includes a microcomputersystem which has a main controlling section (controlling section) 24made up of a CPU (Central Processing Unit), a storing section 25 made upof a ROM (Read Only Memory) 25 a, RAM (Random Access Memory) 25 b, oralike, an input interface 26, an output interface 27, and a motordriving circuit 28 to drive the motor 12.

The main controlling section 24 loads, for example, a control program ordata stored in the ROM 25 a in a working area of the RAM 25 b andcontrols operations of the motor 12.

The collision risk judging section 11 is mounted to judge whether thereis a risk of collision with an obstacle such as a vehicle existing in aforward direction or whether the collision is avoidable or unavoidableand to detect to confirm whether or not collision avoidance operationsincluding a driver's rapid brake operation or rapid handle operation areperformed.

The collision risk judging section 11 measures a distance between thevehicle and the obstacle for every specified time by using a non-contacttype distance sensor such as a laser radar, ultrasonic sensor, or a likeand calculates a relative speed based on a time change of the distance.Then, by dividing the distance by the obtained relative speed, timebefore the collision is computed.

The collision risk judging section 11 judges, when the time of theoccurrence of the collision is within predetermined specified time, thatthere is a risk of collision and outputs a collision risk signal(“immediately before collision” signal).

The collision risk judging section 11, when detecting that collisionavoidance operations including a driver's rapid brake operation, rapidhandle operation, or a like are performed, outputs a collision risksignal.

FIG. 4 is a block diagram showing configurations of the locking signalproducing section (locking signal producing section) 18 of the beltretractor 4. The locking signal producing section 18, as shown in FIG.4, is made up of a microcomputer system which has a detectioncontrolling section 29 made up of a CPU, a storing section 31 made up ofa ROM 31 a, RAM 31 b, or a like, an input interface 32, and an outputinterface 33.

To the locking signal producing section 18 is connected ahorizontal-direction acceleration sensor 34 to detect acceleration Gx ina horizontal direction out of acceleration of a vehicle body andback-forward direction acceleration sensor 35 and the detectioncontrolling section 29 to detect acceleration Gy in a back-forwarddirection out of the acceleration of the vehicle body receivesinformation about acceleration supplied from the horizontal-directionacceleration sensor 34 and the back-forward direction accelerationsensor 35 and, after calculating absolute values |Gx| and |Gy| of theacceleration Gx and Gy based on the acceleration Gx and Gy, calculatestime averages Gxa and Gya of a predetermined time (for example, 2 ms)absolute values |Gx| and |Gy| of the acceleration Gx and Gy, and outputsa locking-signal non-detected signal or a locking-signal detected signalbased on threshold values Gxt and Gyt of a predetermined acceleration.

That is, the detection controlling section 29, when Gxa<Gxt and Gya<Gyt,outputs a locking-signal non-detected signal and outputs a lockingsignal in cases other than the above.

Moreover, in the above embodiment, the threshold values Gxt and Gyt ofthe acceleration are determined in advance in a manner to correspond tooperational conditions of a vehicle body acceleration detecting section.

The detection controlling section 29 loads, for example, a controllingprogram and/or data stored in the ROM 31 a in a working area of the ROM31 b, calculates, for example, time averages Gxa and Gya of absolutevalues of acceleration Gx and Gy, produces a locking-signal non-detectedsignal and a locking-signal, and feeds the produced signals to thecontrolling unit 13.

The program stored in the ROM 31 a includes an acceleration calculatingprogram to calculate the above-described time averages Gxa and Gya and ajudging program to judge which was output, the locking-signalnon-detected signal, the locking-signal, or a like.

In the controlling unit 13, by using an output from the seat beltwearing section 9, setting of a flag in a flag area placed in the RAM 25b is done through the input interface 26.

Also, in the controlling unit 13, when a collision risk signal is fedfrom the collision risk judging section 11 to the input interface 26, a“collision risk flag” installed in the RAM 25B is turned ON. This causesthe main controlling section 24 to start interruption process.

Also, in the controlling unit 13, when a locking-signal is input fromthe locking-signal producing section 18 to the input interface 26, a“locking flag” in the flag area installed in the RAM 25 b is turned ON.Also, when a non-locking signal is input, the “locking flag” is turnedOFF.

Also, in the controlling unit 13, a voltage output from thepotentiometer 23 is A-D (Analog to Digital) converted by the inputinterface 26 in a predetermined period. The input interface 26 in whicha CPU is embedded monitors the converted output voltage data.

For example, a rotational state of the reel shaft 16 is judged based ona difference between a previous value and a present value of the outputvoltage data and a drawing flag of the seat belt 3 or a reeling flag ofthe seat belt 3 is set in the flag area of the RAM 25 b based on whetherthe difference between the previous value and present value of theoutput voltage is positive or negative.

Alternatively, by operations of a DMA (Direct Memory Access), outputvoltage data is written in an area in which a rotational amount isstored. A change in a drawing direction appearing when the seat belt 3has been reeled corresponds to looseness of the seat belt 3. This amountof looseness of the seat belt 3 is written in an area in which a beltlooseness is stored.

Moreover, in the controlling unit 13, a current value flowing throughthe motor 12 is detected by a current detector installed in the motordriving circuit 28 as a voltage value corresponding to the current. Thisvoltage value is A/D converted in a predetermined period in the inputinterface 26 and is written in an area in which a motor current isstored in the RAM 25 b by operations of the DMA. Since a current of themotor 12 is related to rotational torque of the motor 12, the rotationaltorque can be estimated by the current value loaded thereon. Therotational torque of the motor 12 serves as drawing force of the seatbelt 3. The main controlling section 24, when a predetermined conditionset in the control program is met, feeds an instruction for normalrotation of the motor 12, an instruction for reverse rotation, and aninstruction for stopping of driving to the output interface 27.

The output interface 27 produces a gate signal corresponding to theseinstructions and supplies these instructions to the motor drivingcircuit 28. In the case of normal rotation of the motor 12, G1 and G2are set to be “H” and “L” respectively. In the case of reverse rotation,the G1 and G2 are set to be “L” and “H” respectively. In the case of thestopping of driving of the motor 12, the G1 and G2 are set to be “L” and“L”.

FIG. 6 is a circuit diagram showing configurations of the motor drivingcircuit 28 of the controlling unit 13. The motor driving circuit 28, asshown in FIG. 6, is a transistor bridge circuit made up of fourtransistors including PNP-type transistors Q1 and Q2 and NPN-typetransistors Q3 and Q4.

Emitters of the transistors Q1 and Q2 are connected to each other and asupply power Vc is fed to a connection point. Emitters of thetransistors Q3 and Q4 are connected to each other and a ground potentialis fed to the connection point. A level of each of output currents fromthe transistors Q3 and Q4 is detected by a current detector CT and, as aresult, a level detection signal is transmitted to the input interface26. The level detection signal is A/D converted by the input interface26 and is written in an area in which a belt tension is stored in theRAM 25 b by operations of the DMA. A load current value flowing throughthe motor 12 is related to torque and, therefore, a tension of the seatbelt 3 can be estimated from this.

Collectors of the transistor Q1 and Q2 are connected to each other via adiode D1. The collectors of the transistors Q2 and Q3 are connected toeach other via the diode D2. A base of the transistor Q1 is connected toa collector of the transistor Q4 via a bias resistor R1. A base of thetransistor Q2 is connected to the collector of the transistor Q3 via thebias resistor R2. The motor 12 is connected between the collectors ofthe transistors Q1 and Q2.

In the motor driving circuit 28, when an instruction for normal rotationof the motor 12 is fed to each gate of the transistors Q3 and Q4 fromthe input interface 33, the transistor Q3 is brought into conduction andthe transistor Q4 is brought into non-conduction. The collector of thetransistor Q3 is put into a ground level and operates to bias a base ofthe transistor Q2 through the resistor R2 to make the base be at a lowlevel (approximately ground level) and the transistor Q2 be brought intoconduction. The collector of the transistor Q4 is changed approximatelyto be a level of supply power and makes a base of the transistor Q2become high in potential level and makes the transistor Q1 be broughtinto conduction. As a result, a forward-direction current path is formedin paths of the power source Vc, transistor Q2, motor 12, diode D1,transistor Q3, and the ground, and the motor 12 rotates in a directionin which the seat belt 3 is reeled.

When an instruction for reverse rotation is fed to each of gates of thetransistors Q3 and Q4 from the output interface 27, the transistor Q3 isbrought into non-conduction and the transistor Q4 is brought intoconduction.

The collector of the transistor Q4 is changed to be at a ground level bybeing brought into conduction and biases, through the resistor R1, thebase of the transistor Q1 so as to be at a low level, thus making thetransistor Q1 be brought into conduction. The collector of thetransistor Q3 is changed to be approximately at a supply source leveland biases, through the resistor R1, the base of the transistor Q2 to beat a high level, thus making the transistor Q2 be brought intoconduction.

As a result, a forward-direction current path is formed in paths of thesupply power source Vc, transistor Q1, motor 12, diode D2, transistorQ3, and ground, and the motor 12 rotates in a direction of drawing outthe seat belt 3.

A supply of a driving stop instruction signal fed from the outputinterface 27 to each gate of the transistors Q3 and Q4 makes both thetransistors Q3 and Q4 be brought into non-conduction. When thetransistor Q3 is changed from its conduction state to its non-conductionstate, the level of the collector of the transistor Q3 is raised fromits ground level to its supply power level and the base of thetransistor Q1 is biased to be at a high potential and the transistor Q2is driven into cutoff. Similarly, when the transistor Q4 is changed fromits ground level to its supply power level and the base of thetransistor Q2 is biased to be at a high potential, the transistor Q12 isdriven into cutoff. Thus, when the driving stop instruction is supplied,each transistor making up the bridge is brought into non-conduction.

Next, by referring to FIG. 7 to FIG. 15, mechanical configurations ofthe belt retractor 4 of the embodiment are described.

FIG. 7 is an exploded perspective view partially showing configurationsof a belt retractor 4. FIG. 8 is an exploded perspective view showingconfigurations of another portion of the belt retractor 4. FIG. 9 is across-sectional view showing configurations of a belt locking mechanism17 of the seat belt device 1. FIG. 10 is a diagram explainingconfigurations of the ratchet wheel 56 of the belt locking mechanism 17.FIG. 11 is a diagram showing configurations of a locking arm 63 of thebelt locking mechanism 17. FIG. 12 is a diagram showing a locking arm 63of the belt locking mechanism 17. FIGS. 13 to 15 are diagrams explainingoperations of the belt locking mechanism 17.

As shown in FIG. 7, the retractor base 41 is ⊃-shaped and reeling-shaftthrough-holes are formed in its side plates 41 a and 41 b facing eachother and the reel 15 serving as a reeling shaft around which the seatbelt 3 is wound is put between reeling-shaft through-holes in a state inwhich a shaft of the reel 15 is inserted into the reeling-shaftthrough-hole and in a manner to be supported by the shaft and to rotatefreely.

Moreover, an associated internal tooth 42 of the reeling-shaftthrough-hole formed in the side plate 41 a is formed in an inner edge ofthe reeling-shaft through-hole and a ring member 43 is placed on anoutside of the reeling-shaft through-hole. Drawing process is performedin the ring member 43 along its inner edge and, when the ring member 43is fixed by rivets 44 to an outside face of the side place 41 a, anaxial clearance between the associated internal tooth 42 and the inneredge of the reeling-shaft through-hole appears.

On a side of the side plate of the retractor base 41 is placed a beltlocking mechanism 17 used to inhibit drawing of the seat belt 3 in caseof emergency. Moreover, on a side of the side plate of the retractorbase 41 is placed a power transfer unit 47 including a pulley 19,reeling spring 46, potentiometer 23, or a like being connected to theshaft (corresponding to the reel shaft 16) 45 to be driven by the motor12 via the power transfer belt 21.

The reel 15 is an approximately cylindrical-shaped reeling shaftintegrally formed by aluminum alloy or a like. In the drum portion ofthe reeling shaft 48 around which the seat belt 3 is wound is placed aslit-shaped aperture 48 a which penetrates the reeling shaft 48 in adirect-diameter direction for keeping an end of the seat belt 3 beinginserted and maintained therein. Moreover, in an outer edge of the reel15 is attached a flange member 49 formed by an another material toprevent winding perturbation of the seat belt 3.

Furthermore, a position for drawing and inserting of the seat belt 3being wound around an outer edge of the reel 15 attached to theretractor base 41 is controlled by the passage of the seat belt 3through a seat belt guide 51 placed in an upper portion on a rear plateof the retractor base 41.

On both sides of the reel 15 is placed a rotational supporting shaft inan protruded state and in a manner to rotate freely and, as shown inFIG. 8, on an end side of a sensor of the reel 15 is inserted, bypressure, a supporting shaft pin 52 configured as a separate body toserve as the rotational supporting shaft.

In an end face on the sensor side of the reel 15 is attached, as shownin FIG. 7, a supporting shaft 54 in a manner to be protruded whichsupports, by a shaft, a pawl 53 serving as a locking member being ableto be attached to a connecting inner tooth 42 formed on a side plate.

Also, when the pawl 53 rotates in an oscillating manner in a directionof being connected to the associated inner tooth 42, positioning of anend on the oscillating side of the pawl 53 and a rear end section 53 eof the pawl 53 placed on an opposite side is made and, a pressurereceiving section 55 to receive pressure when a large load is imposedbetween the pawl 53 and the connecting inner tooth 42 is placed at anend on the sensor side of the reel 15.

Moreover, at an end on a side of the sensor of the reel 15 is placed astopping protruded section 58 used to control the rotation of theoscillating lever member 57 attached to the ratchet wheel 56 in anoscillating manner serving as a latching member of the locking operatingmeans in a counterclockwise direction.

The concave section 59 is a relief used to prevent interference among atension coil spring 61 to give momentum to rotation in a direction(direction shown as an arrow X2 in FIG. 8) in which the seat belt 3 ofthe ratchet wheel 56 is drawn, an arm section 63 c of the locking arm 63configured to press a sensor spring 62 described above, and the reel 15.

At an oscillating end of the pawl 53 being able to be connected in amanner to correspond to the connecting inner tooth 42 formed on the sideplate 41 a is integrally formed a connecting tooth 53 c. Also, a shafthole 53 a being fitted, in a manner to have play, in the supportingshaft 54 penetrates a center portion of the pawl 53 and a connectingprotruded section 53 b being positioned on the oscillating side and apressure protrusion 53 d positioned on the rear end of the pawl 53 areplaced on a side of the sensor of the pawl 53.

That is, since the shaft hole 53 a is attached to the supporting shaft54 in a manner to have play, the pawl 53 is supported by the supportingshaft 54 in a state in which the pawl 53 can rotate in an oscillatingmanner and can move relatively by a specified amount. To a stop hole 64b being a through hole of a holding plate 64 which the supporting pin 52inserted by the reel 53 penetrates is connected an end of the supportingshaft 54 in a state in which the end is crimped and the holding plate 64prevents the pawl 53 from coming up from an end of the reel 15.

Also, an end of the connecting protruded section 53 b of the pawl 53 isinserted into a cum hole 56 a placed outside the holding plate 64 andformed in the ratchet wheel 56 supported by the supporting pin 52 in amanner to rotate freely.

Here, when the ratchet wheel 56 rotates in a direction (direction shownby an arrow X1 in FIG. 8) in which the seat belt 3 relative to aposition of the reel 15 is reeled, the cum hole 56 a acts so as to movean end of the connecting protruded section 53 b outside in a radiusdirection from the rotational center of the reel 15, the pawl 53 is madeto rotate around the supporting shaft 54 toward a direction (directionshown by the arrow Y1 in FIG. 7) in which the connecting inner tooth 42formed in the side plate 1 a is connected.

That is, the locking means is so configured that the pawl 53 is made torotate, in a oscillating manner, in a direction in which the connectinginternal tooth 42 is connected and the connecting tooth 53 c is coupledto the connecting tooth 42, thus inhibiting rotation of the reel 15.

The ratchet wheel 56, as shown in FIGS. 8 and 9, is a ratchet whosecentral hole is supported by a supporting shaft pin 52 in a manner torotate freely and in a portion surrounding the ratchet is formed aratchet tooth 56 b to be connected to a sensor arm 65 of a vehicle bodyacceleration detecting section 50.

Also, a flange section 52 a of the supporting shaft pin 52 is configuredto support a central hole 66 a of an inertia plate 66 being adiscoidal-shaped inertial member that makes up a belt drawingacceleration detecting section 40 serving as an inertia detecting meansused to detect a drawing acceleration of the seat belt 3. The stoppingnail section 67 formed in an edge of a central hole of the ratchet wheel56 toward an outside of the belt retractor 4 performs positioning in athrust direction of the inertia plate 66 in a manner to be connected toa connecting hole 66 b.

To a long hole 68 formed on the ratchet wheel 56 is connected aconnecting extruded section 69 of the inertia plate 66 and one end ofthe edge 68 a of the long hole 68 performs positioning processing in arotational direction of the inertia plate 66 at the time when the beltlocking mechanism 21 is not working (see FIG. 10).

On an outer side of the ratchet wheel 56 are formed a shaft section 71to support the locking arm 63 so as to be rotated freely and a springhook section 72 in a manner to be protruded. In the inertia plate 66, asshown in FIG. 12 and FIG. 14, an aperture 73 through which the springhook section 72 is to be inserted is formed.

In the aperture 73 is formed the inertia plate 66 in a long hole statein which the inertia plate 66 is able to rotate relatively to theratchet wheel 56 and at one of ends of the inertia plate 66 is placed aspring hook section 74 corresponding to the spring hook section 72.

Into these pairs of the spring hook sections 72 and 74 are inserted acompressed coil spring 75 in a fitted manner. The compressed coil spring75, as shown in FIG. 13, serves to give moment so that a state (that is,non-locked state) in which the connecting extruded portion 69 of theinertia plate 66 contacts another end edge of the long hole 68 formed inthe ratchet wheel 56 in a straightly-struck manner is maintained.

In an inner face side of the ratchet wheel 56 is formed a springstopping section 76 used to stop another end of the tension coil spring61 whose one end is connected to a stopping section 64 c of the holdingplate 64 and the tension coil spring 61 gives moment to the rotation ofthe reel 15 in a direction in which the seat belt 3 of the ratchet wheel56 is drawn.

The locking arm 63 includes, as shown in FIG. 11, a connecting coil 63 bthat can be engaged with an inertia tooth gear 77 a of a gear case 77and the arm section 63 c that pushes, by pressure, alongitudinal-direction central portion of the sensor spring 62 bothsides of which are supported by a pair of hook sections 56 d mounted onan outer side of the ratchet wheel 56.

Here, the locking arm 63 makes up a connecting member in which aconnecting nail 63 d engages with the inner tooth gear 77 a to stoprotation in a direction in which the seat belt 3 of the ratchet wheel 56is drawn. The connecting nail 63 b is pushed, by momentum power of thesensor spring 62, to the straightly-struck contacting section 78 of theinertia plate 66.

Moreover, an aperture is formed in the ratchet wheel 56 corresponding toan oscillation range of the arm section 63 c and the arm section 63 cpenetrates the aperture, which ensures connection between the armsection 63 c and the sensor spring 62.

The straightly-struck contacting section 78 is so constructed that afirst cum face 78 a along which a rear portion 63 d of the connectingnail 63 d of the locking nail 63 b of the locking arm 63 slides and inwhich the rotation of the inertia plate 66 does not affect operations ofthe locking arm 63 and a second cum face 78 b that oscillates thelocking arm 63 so that the connecting nail 63 d engages with the inertiatooth gear 77 a depending on a delay in the rotation of the inertiaplate 56 relative to the rotation of the reel 15.

When the belt locking mechanism 21 is in a non-locked state, the firstcum face 78 a contacts the rear portion 63 d of the locking arm 63 and,until the delay in the rotation of the inertia plate 66 relative to therotation of the reel 18 exceeds a predetermined amount, the rear portion63 d of the locking arm 63 does not contact, in a straightly-struckmanner, the second cum face 78 b.

A length (that is, an amount of the rotation of the inertia plate 66with the rear portion 66 d being in contact with the first cum face 68 ain a sliding manner) of the first cum face 68 a is set at a degree towhich, even if a delay in the rotation occurs due to inertia force thatacts the inertia plate 66 when a total amount of the seat belt 3 ishoused, the rear portion 63 d of the locking cum 63 does not reach thesecond cum face 78 b by such the delay in the rotation.

Moreover, in the locking arm 63 of the embodiment, a straightly-struckcontacted nail 63 e is formed at the oscillating end being opposite tothe connecting nail 63 d. A step portion 81 with which thestraightly-struck contacted nail 63 e can be in contact is formed in theinertia plate 66 in a straightly-struck contacted manner so as tocorrespond to the straightly-struck contacted nail 63 e.

The step portion 81, when the inertia plate 66 is in a non-locking stateand in an initial position, the rotation of the locking arm 63 iscontrolled in a locking direction by a straightly-struck contact of thestraightly-struck contacted nail 63 e.

As shown in FIGS. 14 and 15, if an amount of rotational delay exceedinga predetermined amount occurs in the inertia plate 66 and if the rearportion 63 d of the locking arm 63 comes in contact with the second cumface 78 b, by pressure-pushed action, the locking arm 63 can beoscillated in a locking direction.

Additionally, the oscillating lever member 57 whose shaft hole 57 a issupported by the shaft is placed on the supporting shaft 82 beingprotruded in an inner side face of the ratchet wheel 56. The oscillatinglever member 57 is put between the reel 15 and the ratchet wheel 56 sothat the counterclockwise rotation is controlled, when necessary, by theconnecting protruded portion 58 placed at an end surface on the sensorside of the reel 15 and so that the clockwise rotation is controlled,whenever necessary, by mounting the pressure-pushed protruded portion 53d placed on the sensor side of the pawl 53 in an protruded manner is putbetween the supporting shaft 82 and the stopping extruded portion 58.

Moreover, in a central portion of the gear case 77 placed on an outerside of the inertia plate 66 is placed a shaft supporting section 77 aand, at the bottom face of a shaft supporting section 77 b, a flangesection 52 a of the supporting pin 52 is in contact in astraightly-struck contacted manner and is used as a face for positioningin a shaft line direction of the reel 15. Also, in a lower portion ofthe gear case 77 is formed a box-shaped section 83 that houses a vehiclebody acceleration detecting section 50 serving as an inertia detectingmeans to detect acceleration of a vehicle body. Furthermore, on an outerside of the side plate used to cover the gear case 77 is placed a sensorcover 89, as shown in FIG. 8.

FIG. 16 is a flowchart explaining operations of the seat belt device 1.FIG. 17 is a flowchart explaining operations of the locking signalproducing section 18.

Next, operations of the seat belt device 1 of the embodiment aredescribed by referring to FIGS. 16 and 17.

The main controlling section 24, by executing a main program,periodically monitors a wearing flag of the seat belt 3 (Step ST 11,FIG. 16). In Step ST11, when the seat belt wearing flag is in an OFFstate, the process is terminated as it is and, when the seat beltwearing flag is in an ON state, the routine proceeds to Step ST12 andthe main controlling section 24 judges whether or not there is a risk ofcollision or whether necessity of collision avoidance operations existsaccording to setting of the collision risk flag.

In Step ST12, when the collision risk flag is in an OFF state, theroutine is terminated as it is and, when the collision risk flag is inan ON state, the routine proceeds to Step ST13 and the motor drivingcircuit 28 is controlled and the motor 12 is made to rotate and to bedriven and the seat belt 3 is reeled to raise tension. This enablesremoval of looseness of the seat belt 3 to some extent.

In Step ST14, when the tension of the seat belt 3 reaches apredetermined level, the main controlling section 24 periodicallymonitors the locking flag. The controlling section 24 judges whether ornot a locking signal (or non-locking signal) is input according tosetting or non-setting of the locking flag.

Moreover, the tension of the seat belt 3 is judged by reading a samplevalue written in a current value area in the RAM 25 b of the storingsection 25.

If the locking flag is in an OFF state, the routine proceeds to StepST16 and, if the locking detecting flag is in an ON state, the routineproceeds to Step ST15 and the main controlling section 24 checks timeelapsed after the tension of the seat belt 3 has reached a predeterminedlevel while continuing reeling operations of the seat belt 3 and judgeswhether a predetermined duration time has elapsed or not. When thepredetermined duration time has not yet been reached, the routine isreturned back to Step ST14 and, when the predetermined duration time haselapsed, the routine proceeds to Step ST16 That is, the process in theStep ST15 is executed until a locking signal is not input.

In Step ST15, for example, the belt locking mechanism 17 is in alockable state and the rotation of the ratchet wheel 56 in a directionof drawing the seat belt 3 is inhibited.

However, while the seat belt 3 is reeled by the motor 12 and the reel 15is rotating in a reeling direction, the connecting protruded section 53b of the pawl 53 and the inner tooth 42 of the side plate 41 a are keptin a non-connected state.

In Step ST16, the main controlling section 24 provides an instructionfor decelerating the motor 12 to the output interface 27. This causes adecrease in currents to be fed from the motor driving circuit 28 to themotor 12 and reductions in driving force of the motor 12, thus loweringtension of the seat belt 3. Moreover, by reversing the rotation of themotor 12, the reduction in driving force may be achieved.

Here, even if the judgement is made that a locking signal is not inputafter a rise of the tension in the Step ST13, that is, even if thetension of the seat belt 3 is raised by outputting of an erroneouscollision risk signal, by the process of this Step ST16, the process ofimmediate control of lowering the tension of the seat belt 3 isperformed and, therefore, it is possible to avoid occurrence of givingan unpleasant feeling to a vehicle occupant A caused by needlessrestraining.

Also, when the tension of the seat belt 3 is lowered in this Step ST16after the predetermined duration time has elapsed in the Step ST15, itis possible to avoid the occurrence of giving the unpleasant feeling tothe vehicle occupant A caused by the comparatively long continuation ofthe state in which the tension of the seat belt 3 is high when a lockingsignal is input, for example, along the steep sloping road. Also, thedegradation of the motor 12 can be prevented. After that, when thetension of the seat belt 3 is lowered to a value occurring before therise in the tension of the seat belt 3 and the main controlling section24 provides an instruction for stopping the motor 12 to the outputinterface 27. This causes stopping of a supply of currents from themotor driving circuit 28 to the motor 12 and the motor 12 is stopped.

Next, operations of the locking signal producing section 18 aredescribed by referring to FIG. 17.

First, the detection controlling section 29, in the Step ST21, receivesinformation about acceleration from the horizontal-directionacceleration sensor 34 and back-forward direction acceleration sensor 35and calculates absolute values |Gx| and |Gy| of the acceleration Gx andGy based on the accleration Gx and Gy and then obtains time averages Gxaand Gya for a predetermined time (for example, 2 ms) of absolute values|Gx| and |Gy| of the acceleration Gx and Gy.

Next, in the Step ST22, a locking signal non-detected signal or alocking signal is output based on threshold values Gxt and Gyt ofacceleration set in advance. That is, the detection controlling section29, when Gxa<Gxt and Gya<Gyt, the routine proceeds to Step ST23 and alocking signal is output and, in the case other than this, the routineproceeds to Step ST 24 and non-locking signal is output. The detectioncontrolling section 29 terminates the process after having output alocking-signal non-detected signal or a locking signal. Moreover, in theembodiment, the threshold values Gxt and Gyt of acceleration arepredetermined according to operating conditions of the vehicle bodyacceleration detecting section 50.

According to this example, even if a collision risk signal is outputerroneously from the collision risk judging section 11, unless a lockingsignal is output from the locking signal producing section 18, controlis exerted so that the tension of the seat belt 3 is immediately loweredand, therefore, it is possible to avoid occurrence of giving anunpleasant feeling to the vehicle occupant A caused by needlessrestraining for a comparatively long time.

Moreover, even if a locking signal is output from the locking signalproducing section 18, reeling of the seat belt 3 is continued for apredetermined duration time for reeling by the motor 12 even after thetension of the seat belt 3 reaches a predetermined tension and,therefore, when a non-locking signal is output within the reelingcontinuous time, even if the tension of the seat belt 3 is lowered,drawing of the seat belt 3 is not locked. As a result, it is possible toprevent the occurrence of giving an unpleasant feeling to the vehicleoccupant A caused by restraining of the vehicle occupant A occurringwhen the seat belt 3 is again reeled to release the drawing locking.

Moreover, unlike in the case of the conventional technology in which thereeling continuation time is set at fixed time including the time atwhich a condition for locking of drawing is met and, during the fixedtime, the driving operation for reeling is continued, in thisembodiment, so long as the locking signal is being output from thelocking signal producing section 18, the driving operation for thereeling by the motor 12 is continued and, therefore, needless rise inthe tension of the seat belt 3 can be prevented and wasteful restrainingtime can be saved.

Also, by stopping the driving operation for reeling to lower the tensionof the seat belt 3 after the predetermined reeling continuation time haselapsed, for example, a lockable state occurs in a long steep slopingroad and, when the locking signal is output, a state in which thetension of the seat belt 3 is high continues comparatively long, thuspreventing occurrence of giving an unpleasant feeling to the vehicleoccupant A. Also, it is possible to prevent breakage and/or degradationof the motor 12 caused by a rise in temperatures by long operation forreeling and to achieve a long life.

Second Embodiment

FIG. 18 is a diagram showing configurations of a belt retractor of aseat belt device of the second embodiment. FIG. 19 is a diagramexplaining configurations of a vehicle body acceleration detectingsection and a locking signal producing section making up the seat beltdevice being in a non-locked state. FIG. 20 is a diagram explainingconfigurations of the vehicle body acceleration detecting section and alocking signal producing section making up the seat belt device being ina locked state. FIG. 21 is a diagram explaining configurations of thelocking signal producing section. FIG. 22 is a circuit diagram showingconfigurations of the locking signal producing section and lockingsignal outputting section.

The seat belt device of the second embodiment differs from that of thefirst embodiment in that, unlike in the case of the first embodiment inwhich a main controlling section judges whether or not the tension islowered based on a locking signal output from the locking signalproducing section mounted separately from a belt locking mechanism, alocking signal showing a start of a locking mechanism is output from thevehicle body acceleration detecting section making up a lockingmechanism. Configurations other than above are the same as those in thefirst embodiment and their descriptions are omitted accordingly.

The seat belt device 1A of the second embodiment, as shown in FIG. 18,includes a controlling unit 13A to control a motor (belt adjusting unit)12 used to reel a seat belt 3 or a like, a reel 15 to wind the seat belt3 around a frame 14, a reel shaft (restraining limiting means) 16 whoseleft end portion is connected to the reel 15 and serving as a centralshaft for rotation of the reel 15 is mounted in a manner to rotatefreely and a belt locking mechanism 17A (belt locking mechanism) mountedat a right end of the reel shaft 16 to lock drawing of the seat belt 3.

Moreover, to the controlling unit 13A is connected the locking signalproducing section 18A that produces a locking signal and supplies theproduced signal when locking of drawing the seat belt 3 is detected bythe belt locking mechanism 17A.

Here, a sensor cover 50 a and ball weight 86 also serves as composingelements of the vehicle body acceleration detecting section 50.

The locking signal producing section 18A of the second embodiment, asshown in FIG. 19 to FIG. 21, has the ball weight 86 made of a conductorbeing held by the ball holding action 59 formed at the bottom of thesensor cover 50 a, four electrode pieces 88 a, 88 b, 88 c, and 88 d, andlocking signal outputting section 89.

In the locking signal outputting section 89, as shown in FIG. 22, fiveresistors 89 a to 89 e are connected in series in this order and oneterminal a1 of the resistor 89 a is connected a power supply, oneterminal a6 of the resistor 89 e is connected to aground and to aconnecting point a5 between the resistor 89 d and resistor 89 e isconnected a non-inverted input terminal of a comparator 89 f.

Here, the one terminal a1 of the resistor 89 a, a connecting point a2between the resistor 89 a and the resistor 89 b and a connecting pointa4 between the resistor 89 c and the resistor 89 d are connectedrespectively to the electrode pieces 88 a, 88 b, 88 c, and 88 d.

Also, to an inverted input terminal of the comparator 89 f is applied areference voltage Vr. In the embodiment, Vr=( 5/12) RV (“V” is supplypower). Moreover, an output terminal of the comparator 89 f is connectedto a power supply through a resistor 89 g and to the controlling unit13A.

Next, operations of the seat belt device 1A of the embodiment aredescribed by referring to FIG. 19 to FIG. 22.

In a normal state (for example, in the case where a vehicle accelerationincluding deceleration is a predetermined value or less), the ballweight 86 is placed on a volcano-shaped ball holding groove formed inthe ball holding section 50 p in a safe manner and all the electrodes 88a, 88 b, 88 c, and 88 d are intact with the ball weight 86. Therefore,all the electrodes 68 a, 88 b, 88 c, and 88 d are shorted and “H (high)”level signal (non-locking signal) is output from the output terminal ofthe comparator 89 f. At this point, as shown in FIG. 19, a stoppingprotrusion 65 a does not engage with a ratchet tooth 56 b of a ratchetwheel 56.

Momentum is given to the ratchet wheel 56 by momentum power of a tensioncoil spring being put, in a hung manner, between a spring hung stoppingsection 76 and a spring peg section 64, to a direction of drawing theseat belt relative to the reel 15 and momentum is given to the pawl 53in which a connecting protrusion 53 b is connected to a cum hole 56 a,in a direction of being not connected to a connecting internal tooth 42.As a result, the reel 15 can be rotated and the seat belt 3 can beretracted freely.

When vehicle acceleration (including deceleration) exceeds apredetermined value, the ball weight 86, as shown in FIG. 20, isdisplaced in the ball holding section 50 p and is run on an edge of aball holding groove 50 s and is pushed upward in the drawing and, out ofelectrodes 88 a, 88 b, 88 c, and 88 d, for example, the electrode piece88 d is separated from the ball weight 86. Therefore, from an outputterminal of the comparator 89 f is output an “L” level signal (lockingsignal). When the ball weight 86 is pushed up, a sensor arm 65 movesupward in the drawing and the connecting protrusion 65 a engages withthe ratchet tooth 56 b of the ratchet wheel 56.

Due to this, the rotation in a direction of drawing the seat belt of theratchet wheel 56 can be inhibited. However, when the seat belt 3 isreeled by the motor 12 and the reel 15 rotates in a reeling direction,the connecting protrusion 53 b of the pawl 53 is kept in a state inwhich the connecting protrusion 53 b is not connected to the internaltooth 42 of the side plate 41 a.

Thus, a locking signal is supplied to the controlling unit 13A from thelocking signal outputting section 89 depending on a locking state andnon-locking state of the belt locking mechanism 17A. As described in thefirst embodiment, the controlling unit 13A exerts control of the tensionof the seat belt 3 according to existence or non-existence of inputtingof the locking signal (non-locking signal). According to configurationsof the embodiment, approximately the same effect obtained in the abovefirst embodiment can be achieved in the second embodiment.

Third Embodiment

FIG. 23 is a diagram explaining configurations of a seat belt device ofa third embodiment of the present invention. Configurations of the seatbelt device 1B of the third embodiment differ from those of a seat beltdevice of the first embodiment in that an electric transmission winch isplaced which serves as a belt adjusting unit to draw in or retract theseat belt toward a side of a buckle. Configurations of the seat beltdevice of the third embodiment other than above are the same as those ofthe first embodiment and their descriptions are omitted.

The seat belt device (vehicle occupant restraining and protectingapparatus) 1B of the third embodiment, as shown in FIG. 23, includes anelectric transmission winch 91, as the means for drawing in or out theseat belt 3 toward a side of the buckle 6, which has a motor 91 a and areel 91 b to reel a wire 91 c directly connected to the buckle 6. Normaland reverse rotation of the motor 91 a enables the wire 91 c to be drawnout and retracted.

The controlling section 28, instead of driving the motor 15, drives themotor 01 a of the electric transmission winch 91 to remove looseness ofthe seat belt 3. In this case, it is also possible to estimate a tensionof the seat belt 3 by detecting a current value of the motor 91 a.

Thus, according to the third embodiment, approximately the same effectsas obtained in the first embodiment can be also achieved. Additionally,since a length of a drawn-out portion of the seat belt 3 is decreasedmore compared with the case in which an end of the seat belt 3 is fixedto a vehicle body, looseness of the seat belt 3 can be promptly removed.

Fourth Embodiment

FIG. 24 is a diagram explaining configurations of a seat belt device ofa fourth embodiment of the present invention.

Configurations of the fourth embodiment differ from those of the thirdembodiment in that an electric transmission winch serving as a beltadjusting unit is placed on a side of an anchor to which an end of theseat belt is fixed. Configurations of the seat belt device of the fourthembodiment other than above are the same as those of the thirdembodiment and their descriptions are omitted. In the seat belt (vehicleoccupant restraining and protecting apparatus) 1C of the fourthembodiment, as shown in FIG. 24, the electric transmission winch 91serving as an adjusting means for removing looseness of the seat belt isplaced on a side of the anchor (lapping belt fixing portion) to which anend of the seat belt 3 is fixed.

Thus, according to the fourth embodiment, approximately the same effectas obtained in the first embodiment can be also achieved.

It is apparent that the present invention is not limited to the aboveembodiments but may be changed and modified without departing from thescope and spirit of the invention. For example, in the above embodiment,to lower tension of the seat belt, driving force of a motor 12 isdecrease, however, the motor 12 may be stopped or rotated in a reversedirection.

Also, in the above embodiment, the motor 12 is used as a means foradjusting the seat belt, however, a spring can be employed as a powersource. Also, a belt adjusting unit may be attached to a belt retractor4 or to a place other than that of the belt retractor 4. In this case,the belt adjusting unit may be placed, for example, on a buckle or on alapping belt fixed section. Also, for example, a controlling section 24has also a function of judging a risk of collision or a like of acollision risk judging section 11.

Also, in the collision risk judging section 11, detection of operationsof avoiding collision including the rapid operation of a brake and of ahandle may be made based on information about acceleration fed from ahorizontal-direction acceleration sensor 34 and a forward-backacceleration sensor 35. Also, the belt retractor 4 may be placed not inthe lower portion of a center pillar of a vehicle but on a seat.

Also, in the first embodiment, in a locking signal producing section 18,the locking signal may be output to a controlling unit based onacceleration of drawing the seat belt 3 in addition to vehicle bodyacceleration.

In the second embodiment, the locking signal is output to thecontrolling section 13A in synchronization with operations of thevehicle body acceleration detecting section 50. In addition to this, alocking signal may be output to the controlling unit in synchronizationwith operations of the belt drawing acceleration detecting section 40.

Moreover, in the above third and fourth embodiments, wire may be drawnin by a torsion bar driven by the motor in a rotational manner and a nuton which a reciprocating movement on this torsion bar is made to be usedas a tension variable means. Furthermore, as shown in FIG. 25, the beltretractor 4 of a belt retractor 1D may be attached not in the lowerportion of a center pillar of a vehicle but on the seat.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a vehicle that moves on a roadat high speed.

1. A restraining and protecting apparatus for a vehicle occupantcomprising: a seat belt to restrain a vehicle occupant on a seat; a beltadjusting unit to adjust a tensile state in which said vehicle occupantis restrained using said seat belt by increasing or decreasing said seatbelt to be drawn out in length; a belt locking mechanism to prevent saidseat belt from being drawn out by locking said seat belt; animmediately-before-collision signal producing section to produce andoutput an immediately-before-collision signal immediately beforeoccurrence of a collision of said vehicle; a locking signal producingsection to produce and output a locking signal when it is predicted atleast that said belt locking mechanism is in a lockable state whereinhibition of drawing out is made possible when said seat belt is goingto be drawn out; a controlling section to control said belt adjustingunit based on said immediately-before-collision signal to be input andsaid locking signal to be input; and wherein said controlling sectionexerts control in a manner that, when the immediately-before-collisionsignal is input, said belt adjusting unit increases said tensile statein which said vehicle occupant is restrained using said seat belt andthat, when said locking signal is not input, said belt adjusting unitweakens said tensile state in which said vehicle occupant is restrainedusing said seat belt.
 2. The restraining and protecting apparatus for avehicle occupant according to claim 1, wherein said belt lockingmechanism in said lockable state, when said belt adjusting unit iscontrolled by said controlling section so as to increase said tensilestate in which said vehicle occupant is restrained using said seat belt,is put in a state of releasing locking in which said seat belt is ableto be drawn out.
 3. The restraining and protecting apparatus for avehicle occupant according to claim 1, wherein said controlling sectionexerts control so that, while said locking signal is input, said beltadjusting unit increases and maintains said tensile state in which saidvehicle occupant is restrained using said seat belt.
 4. The restrainingand protecting apparatus for a vehicle occupant according to claim 3,wherein said controlling section exerts control so that said beltadjusting unit, when a predetermined time has elapsed after said lockingsignal has been input, weakens said tensile state in which said vehicleoccupant is restrained using said seat belt.
 5. The restraining andprotecting apparatus for a vehicle occupant according to claim 1,wherein said controlling section exerts control when saidimmediately-before-collision signal is input so that said belt adjustingunit increases said tensile state in which said vehicle occupant isrestrained using said seat belt and that said belt adjusting unit, whensaid tensile state in which said vehicle occupant is restrained usingsaid seat belt comes to a tensile state in which said vehicle occupantis restrained to a predetermined extent and when said locking signal isnot input, weakens said tensile state in which said vehicle occupant isrestrained using said seat belt.
 6. The restraining and protectingapparatus for a vehicle occupant according to claim 1, wherein saidlocking signal producing section outputs said locking signal when atleast part of conditions under which drawing of said seat belt isinhibited by said belt locking mechanism is met.
 7. The restraining andprotecting apparatus for a vehicle occupant according to claim 6,wherein said seat belt is locked under a condition that acceleration ina back-and-forth or lateral direction of said vehicle exceeds apredetermined value.
 8. The restraining and protecting apparatus for avehicle occupant according to claim 6, wherein said seat belt is lockedunder a condition that acceleration at which said seat belt is drawn outexceeds a predetermined value.
 9. The restraining and protectingapparatus for a vehicle occupant according to claim 7, wherein saidacceleration includes acceleration in a direction being reverse to adirection of a velocity of said vehicle.
 10. The restraining andprotecting apparatus for a vehicle occupant according to claim 1,wherein said locking signal producing section, when a state in whichsaid belt locking mechanism is in a lockable state is detected, outputssaid locking signal.
 11. The restraining and protecting apparatus for avehicle occupant according to claim 1, wherein said belt adjusting unitincludes a motor to retract said seat belt and wherein said controllingsection, where said immediately-before-collision signal is input,controls said motor to increase its driving power and to increase saidtensile state in which said vehicle occupant is restrained using saidseat belt and exerts control so that, said belt adjusting unit, whensaid locking signal is not input, weakens said tensile state in whichsaid vehicle occupant is restrained using said seat belt.
 12. Therestraining and protecting apparatus for a vehicle occupant according toclaim 11, wherein said controlling section, while said locking signal isinput, controls said motor serving as said belt adjusting unit so as tohave said seat belt retracted.
 13. The restraining and protectingapparatus for a vehicle occupant according to claim 1, wherein saidimmediately-before-collision signal producing section, based on adetection signal obtained from a non-contact type distance sensor,calculates a speed of said vehicle relative to an obstruction existingin a front of said vehicle and, based on a result from calculation,judges as to whether there is a possibility of occurrence of collisionbetween said vehicle and said obstruction and also judges, when there isa possibility of collision, as to whether said avoidance of collision ispossible or not.
 14. The restraining and protecting apparatus for avehicle occupant according to claim 1, wherein saidimmediately-before-collision signal producing section, when a detectionof an operation for collision avoidance is made, outputs saidimmediately-before-collision signal.
 15. The restraining and protectingapparatus for a vehicle occupant according to claim 14, wherein saidimmediately-before-collision signal producing section outputs saidimmediately-before-collision signal when detection of a rapid brakeoperation or a rapid handle operation for collision avoidance is made bybeing recognized that acceleration in a back-and-forth or lateraldirection of said vehicle exceeds a predetermined value.